Grist mill with wiper arrangement



Dec. 16, 1969 c. LENZ 3,484,049

GRIST MILL WITH WIPER ARRANGEMENT Filed March 22, 1967 y l 12 IX 1 IE 25- 131; H f A 1.1., iii? 27 f 18 f 2U 26 /2z. 11. 1 a u 1 i E: 22;

IN VENTOR Cmwd 6112 United States Patent Int. Cl. 1302c 4/0 4, 21/00, 23/02 US. Cl. 24160 1 Claim ABSTRACT OF THE DISCLOSURE A grist mill for the milling of wet malt equipped with wiper blades associated with each crushing roller, the blades being angularly oflset from the roller nip 90 in the direction of rotation and radially spaced from the associated roller a distance which is not greater than one-half of the width of the nip, a portion of the water sprayed into the crushed malt or grist for converting the same to mash being directed toward the edges of the wiper blades to prevent build-up of a film of grist particles on the rollers.

BACKGROUND OF THE INVENTION This invention relates to brewery equipment, and particularly to improvements in a grist mill for the wet milling of malt.

It is common practice to moisten malt prior to milling or crushing, and to mix the crushed malt in the grist mill itself with enough water to form a mash capable of being transported to further processing equipment by means of pumps. The mill is equipped with two cylindrical rollers which are rotated in opposite directions about parallel horizontal axes and define a nip whose width may vary between approximately 0.35 and 0.50 millimeter, depending on the nature of the malt to be crushed, a nip width of 0.40 to 0.48 millimeter being usually most advantageous.

The moist and somewhat glutinous malt is strongly compressed in the nip, and grist particles tend to adhere to the roller surfaces so that a continuous adhering film may ultimately be produced. Film formation is enhanced by irregularities on the roller surfaces, such as knurling resorted to for better milling action. Damage to the bearings of the rollers can result from such films on conventional grist mills when the films cannot be compressed adequately during passage through the nip.

It is the primary object of the invention to limit the thickness of grist films forming on the crushing rollers of the mill, and thereby to avoid damage to the bearings of the rollers.

SUMMARY OF THE INVENTION An otherwise conventional grist mill having two crushing rollers mounted in a mill housing for rotation about respective axes extending in a common horizontal direction and defining a nip therebetween, means for feeding moistened malt to the nip, and means for mixing the grist or crushed malt with water to make a mash, is equipped, according to this invention, with at least one wiper member which extends axially along one of the rollers, and whose free edge is radially spaced from the associated roller a distance not greater than one-half of the spacing of the rollers in the nip. A portion of the water supplied for mixing with the crushed malt or grist is directed in a spray against the edge of the wiper member.

Other features of the invention -will become apparent to those skilled in the art as the disclosure is made in the following detailed description of a preferred em- "ice bodiment of the invention as illustrated in the accompanying sheet of drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing, the sole figure shows a grist mill according to the invention in side elevation, and partly in section.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing in detail, there is shown a largely conventional grist mill whose malt bin 2 is mounted above the mill housing 6 and connected with the housing by a flange 4 at the tapering bottom end of the bin 2, a flanged connection 8 at the top of the housing 6, and a rotary drum feeder 10, conventional in itself and not shown in detail, which is fixedly interposed between the flange 4 and the flanged connection 8.

Two generally cylindrical crushing rollers 12 are journaled in the mill housing 6 so that their parallel axes extend in a common horizontal plane, and the roller surfaces form a nip 13, the width d of which has not been drawn to scale for the sake of convenient pictorial representation. The actual width of the nip is about 0.45 millimeter. The rollers 12 are driven in opposite directions by a motor, not shown, so that their surfaces move downward in the nip.

The mill housing 6 is supported on a frame 26 and tapers conically downward to the intake of a mash pump 14. The grist or crushed malt downwardly discharged from the nip 13 is intimately mixed with water discharged from an orifice of a supply pipe 16 downwardly against a distributor plate 18 which rotates in a horizontal plane atop the extended shaft 20 of the pump 14. Water is supplied at a rate suflicient to form mash, a suspension of the grist in water, which is capable of being discharge under pressure from the pump 14 into a mash conduit 24 when the pump is driven by a motor, not shown, connected to the drive pulley 22 of the pump by a non-illustrated belt.

The structure described so far is known, and its operation is well understood. The invention provides two wiper blades 25 which are mounted between opposite walls of the housing 6 closely adjacent the lowermost portions of the rollers 12 respectively. Each blade extends in a vertical plane through the axis of the associated roller 12 so that it is offset from the nip 13 in the direction of roller movement. The radial spacing 2 between the narrow longitudinal top edge 27 of the blade and the nearest cylindrical surface portion of the associated roller has not been illustrated to scale in the drawing and is approximately 0.20 millimeter, less than one-half of the width d of the nip 13. The blades 25 extend over the entire axial length of the rollers 12 and are exposed to a portion of the water spray rebounding from the upwardly directed face of the distributor plate 18.

Films of grist particles formed on the rollers 12 in the nip 13 during operation of the mill are thus reduced in their combined thickness by the wiping action of the blades 25 to less than the width of the nip 13, and cannot exert sufi'icient radial pressure during their next passage through the nip to damage the non-illustrated bearings of the rollers on the mill housing 6. The material wiped from the rollers 12 by the edges 27 of the blades 25 is washed away by water directed against the blade edges by rebound from the distributor plate 18.

It should be understood, of course, that the foregoing disclosure relates only to a preferred embodiment of the invention, and that numerous modifications or alterations may be made therein without departing from the spirit and the scope of the invention.

3 4 What is claimed is: said orifice and having a face directed toward 1. In a grist mill having a housing, two crushing rollthe orifice, and ers mounted in said hOIlsing for rotation about respective (3) means for rotating said plate about an upright horizontally spaced axes extending in a common direction axis, and defining a nip therebetween, means for feeding moist- 5 (4) said wiper members being upwardly oflset ened malt to said nip, whereby crushed malt is discharged from said face of the distributor plate. from said nip, and means for mixing the crushed malt with water to make a mash, the improvement comprising: References Cited (a) a Wiper member extending axially along each of UNITED STATES PATENTS said rollers, and having a free edge radially spaced from the same, the spacing between said edge and m g p said one roller being not greater than one-half of the 256O837 7/1951 i 6 X spacing of said rollers in said nip, and said wiper clan members being angularly oifset from said nip about FOREIGN PATENTS 90 relative to the assoclated roller axes in a down- 15 207,543 3/1909 Germany Ward dlrectlon; and 1,092,420 11/1960 Germany.

(b) spraying means in said housing for directing a portion of said water in a spray a ainst the ed es of said wiper members, said spraying means inclu ding ROBERT R Primary Examiner 1) a water supply conduit having an orifice in 20 DONALD KELLY, Assistant Examiner said housing below said nip and directed in a downward direction, US. Cl. X.R.

(2) a distributor plate downwardly spaced from 241167, 225 

